Method for scheduling guaranteed bit rate service based on quality of service

ABSTRACT

The disclosure discloses a method for scheduling a Guaranteed Bit Rate (GBR) service based on Quality of Service (QoS) and an apparatus implementing the method, wherein the method comprises the steps of: determining a scheduling priority of an online user according to an average rate of a GBR service of the user in a current Transmission Time Interval (TTI); and scheduling the user in accordance with the determined priority and allocating Resource Block (RB) resources to the user. With the scheduling method of the disclosure, the RB resource can be fully utilized, and the user rate which does not reach the GBR is quickly improved to make as many users as possible to reach the GBR, so as to increase the number of satisfied users in system. For the case in which a Maximum Bit Rate (MBR) is greater than the GBR, on the basis that as many users as possible are made to reach the GBR, the rates of the users can be further improved to increase the number of users with high rates.

TECHNICAL FIELD

The disclosure relates to a scheduling technology of a Guaranteed BitRate (GBR) service, in particular to a method for scheduling a GBRservice based on Quality of Service (QoS).

BACKGROUND

Data with a strict QoS guarantee, such as voice, image, video and othermultimedia service data, is a major concern for a mobile communicationsystem. In order to enable a service to be used by a terminal user withan expected effect, for example, the images should be continuous when auser watches a Video online, the 3^(rd) Generation Partnership Project(3GPP) clearly defines an end-to-end QoS structure in the mobilecommunication system and introduces multiple bearing and processingmechanisms, to guarantee that the mobile communication system can fullydevelop its technical advantages for providing various differentiatedservices for users.

QoS refers to the service quality provided by a system (server) for auser. QoS is for end to end, that is, the evaluation of QoS starts froma Source end and ends at a Target end. QoS parameters of bearer levelinclude QoS Class Identifier (QCI), Allocation and Retention Priority(ARP), GBR, Maximum Bit Rate (MBR) and Aggregated Maximum Bit Rate(AMBR), wherein the QCI is a quantity level used for representingparameters of an access point transmitted and processed by a data packetfor controlling the bearer level, and the main object of the ARP is todecide whether to accept or reject a bearer establishment ormodification request in the case of limited resources. The parameter GBRrepresents a bit rate expected to be provided by a GBR bearer, when atransmission rate of a service is greater than or equal to the GBR, theQoS of the service is satisfied; when the transmission rate of theservice is less than the GBR, the QoS of the service is not acceptable.The parameter MBR limits the bit rate which the GBR bearer can provideand represents an upper limit of the data rate expected to be providedby the GBR bearer.

The GBR bearer is mainly used for services such as voice, video,real-time game, and etc.; however, in order to guarantee the QoS of aservice, it is needed to guarantee the QoS at access network side andthe QoS at core network side. The QoS of the core network side serviceis guaranteed by a transmission priority, while the QoS of the accessnetwork side is guaranteed by allocating sufficient radio resources in aBase Station.

The QoS of the core network side service is easily implemented. However,for the QoS of a GBR service of the access network, the eNodeB decidesthe service priority of each user terminal through scheduling;therefore, the selection of a proper scheduling algorithm plays animportant role on the obtaining of a GBR rate of a user terminal.

At present, there are three common scheduling algorithms at the basestation side: Round Robin (RR) algorithm, Maximum Carrier toInterference (Max C/I) algorithm, and Proportional Fair (PF) algorithm.

The basic idea of the RR algorithm is to guarantee that user terminalsin a cell occupy equal time of radio resources cyclically based on adetermined order to perform communication. Although this algorithmprovides fairest scheduling chances, it can not fully utilize thedifferentiation in the quality of user channels, both the systemresource utilization ratio and the system throughput are very low.Besides, this algorithm does not consider the requirement of the user'sGBR, thus the user's satisfaction degree is very low.

The basic idea of the Max C/I algorithm is to sort all prediction valuesof Channel Quality Indicator (CQI) of users and to schedule the users ina descending order. Although this algorithm can obtain a maximum systemthroughput rate, the service obtained by the user is not fair: a centeruser with good channel conditions would accept services all the time andthe rate thereof would be greater than the GBR, while an edge user withpoor channel conditions has a rate less than the GBR because of failingto obtain scheduling, thus the user's satisfaction degree is low.

The PF algorithm is that the eNodeB schedules one or more terminalshaving greatest Fair Factors (FF). The basic idea of the PF algorithm isto allocate corresponding priorities to users in a cell, wherein theuser with the highest priority in the cell accepts services. The sectorthroughput rate and the service fairness of this algorithm are betweenthe RR algorithm and the Max C/I algorithm.

${{{FairFactor}_{i}(t)} = \frac{{TbSize}_{i}(t)}{{{Throughput}_{i}(t)} + 1}},$wherein FairFactor_(i)(t) represents a FF of UE_(i) at moment t;TbSize_(i)(t) represents a data amount UE_(i) can transmit at moment t;Throughput_(i)(t) represents the throughput of UE_(i) in a time windowwith t as its end. For a User Equipment (UE) with good CQI, with itsincrease of the throughput, the priority would decrease to achievefairness. This algorithm does not consider the requirement of the user'sGBR either.

If a service in a communication system is of stream type, the serviceneeds a GBR. If a service is a non-GBR service and the GBR is notconfigured for the user, then no service is provided for the user whenthe system lacks resources, which results in the user not satisfied.Therefore, a proper GBR is needed to be configured for a user both in aGBR service and a non-GBR service, so that the user can obtain a basicQoS. In this way, extensive operation policies can be provided.

SUMMARY

In view of the problem above, the main object of the disclosure is toprovide a method and apparatus for scheduling a GBR service based onQoS, so that Resource Block (RB) resources can be fully utilized, andthe user rate which does not reach a GBR is quickly improved to make asmany users as possible to reach the GBR rate.

In order to achieve the object above, the technical scheme of thedisclosure is realized by:

A method for scheduling a GBR service based on QoS, and the methodincludes:

a scheduling priority of an online user is determined according to anaverage rate of a GBR service of the user in a current Transmission TimeInterval (TTI); and

the user is scheduled in accordance with the determined priority and RBresources is allocated to the user.

Preferably, determining the scheduling priority of the online useraccording to the average rate of the GBR service of the user in thecurrent TTI may be:

the scheduling priority of the user is determined according to a PFscheduling algorithm in conjunction with QoS of the GBR service of theuser.

Preferably, determining the scheduling priority of the user according tothe PF scheduling algorithm in conjunction with QoS of the GBR serviceof the user may be determining a scheduling priority FF of the useraccording to the following formula:FF=FF_(PF)·FF_(GBR)

where

${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}{{TB}(i)}}{1 + {Th}_{His}}},{{FF}_{GBR} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {Th}_{His}}}},$“·” represents a scalar multiplication, Th_(His) represents an averagerate of the GBR service in N TTIs selected prior to the current TTI,TB(i) represents Transmission Blocks (TBs) transmitted successfully inthe N TTIs, ThresholdGBR represents a GBR reserved proportion set by asystem, and GBR in the numerator of the index represents a guaranteedbit rate configured by the system.

Preferably, Th_(His) is determined according to the following formula:

${{Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2} + \ldots + {{TB\_ m} \cdot {ACK\_ m}}} \right)}{N}},$where N represents a selected window length, m represents a number ofGBR service streams of the user in the N TTIs, TB_1 to TB_m represent TBSizes scheduled once for respective GBR service streams 1 to m in theTTI, and ACK_1, ACK_2 and ACK_m take a value of 1 when a correspondingTB is transmitted successfully and a value of 0 when the correspondingTB fails to be transmitted.

Preferably, scheduling the user in accordance with the determinedpriority and allocating RB resources to the user may be:

retransmission users are scheduled in accordance with a priority order,wherein a number of RBs of each retransmission user depends on aretransmitted TB Size and is not limited by a GBR factor; and

if there are remaining RB resources after all retransmission users arescheduled, new-transmission users are scheduled in accordance with apriority order, and multiple RBs are allocated to each new-transmissionuser according to QoS determined by the GBR service of eachnew-transmission user.

Preferably, allocating multiple RBs to each new-transmission useraccording to the QoS determined by the GBR service of eachnew-transmission user may be:

when determining that the average rate of the new-transmission user isgreater than a Maximum Bit Rate (MBR), the new-transmission user is notscheduled;

when determining that the average rate of the new-transmission user isgreater than or equal to the GBR but less than or equal to the MBR andfurther determining that there are other users with rates less than theGBR in a current cell, a number of RBs for the new-transmission user isdetermined according to a smaller value in the GBR and a Buffer StatusReport (BSR) of the new-transmission user; when determining that theaverage rates of other users in the current cell are all greater than orequal to the GBR, a number of RBs for the new-transmission user isdetermined according to the value in the BSR of the new-transmissionuser, wherein the other users refer to all online users in the servingcell to which the new-transmission user belongs but excluding users justgetting online in the current TTI, retransmission users,new-transmission users already scheduled prior to scheduling thisnew-transmission user, and this new-transmission user itself; and

when determining that the average rate of a new-transmission user isless than the GBR, a number of RBs for the new-transmission user isdetermined according to the value in the BSR of the new-transmissionuser.

Preferably, when determining that the average rate of thenew-transmission user is greater than or equal to the GBR but less thanor equal to the MBR, the method may further include:

when the BSR of the user is greater than the GBR, this user is added toa user list in which the number of RBs for the user is limited and theaverage rate of the user reaches the GBR; and

if there are remaining RB resources after other users are all allocatedwith RB resources, the RB resources are allocated to the user in theuser list of which a limited RB number has reached the GBR.

An apparatus for scheduling a GBR service based on QoS, and theapparatus includes a determining unit and a resource scheduling unit,wherein

the determining unit is configured to determine a scheduling priority ofan online user according to an average rate of a GBR service of the userin a current TTI; and

the resource scheduling unit is configured to schedule the user inaccordance with the determined priority and allocate RB resources to theuser.

Preferably, the determining unit may be further configured to determinethe scheduling priority of the online user according to a PF schedulingalgorithm in conjunction with QoS of the GBR service of the user.

Preferably, the determining unit may be further configured to determinea scheduling priority FF of the user according to the following formula:FF=FF_(PF)·FF_(GBR)

where

${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}\;{{TB}(i)}}{1 + {Th}_{His}}},{{FF}_{GBR} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {Th}_{His}}}},$“·” represents a scalar multiplication, Th_(His) represents an averagerate of the GBR service in N TTIs selected prior to the current TTI,TB(i) represents TBs transmitted successfully in the N TTIs,ThresholdGBR represents a GBR reserved proportion set by a system, andGBR in the numerator of the index represents a guaranteed bit rateconfigured by the system.

Preferably, the determining unit may be further configured to determineTh_(His) according to the following formula:

${{Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\;\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2} + \ldots + {{TB\_ m} \cdot {ACK\_ m}}} \right)}{N}},$where N represents a selected window length, and m represents the numberof GBR service streams of a user in the N TTIs, wherein m is generally 1or 2, TB_1 to TB_m represent TB Sizes scheduled once for respective GBRservice streams 1 to m in the TTI, and ACK_1, ACK_2 and ACK_m take avalue of 1 when a corresponding TB is transmitted successfully and avalue of 0 when the corresponding TB fails to be transmitted.

Preferably, the resource scheduling unit may be further configured to:

schedule retransmission users in accordance with a priority order,wherein a number of RBs of each retransmission user depends on aretransmitted TB Size and is not limited by a GBR factor; and

if there are remaining RB resources after all retransmission users arescheduled, schedule new-transmission users in accordance with thepriority order and allocate multiple RBs to each new-transmission useraccording to QoS determined by the GBR service of each new-transmissionuser.

Preferably, the resource scheduling unit may be further configured to:

when determining that the average rate of a new-transmission user isgreater than an MBR, do not schedule the new-transmission user;

when determining that the average rate of a new-transmission user isgreater than or equal to the GBR but less than or equal to the MBR andfurther determining that there are other users with rates less than theGBR in a current cell, determine a number of RBs for thenew-transmission user according to a smaller value of the GBR and a BSRof the new-transmission user; when determining that the average rates ofthe other users in the current cell are greater than or equal to theGBR, determine a number of RBs for the new-transmission user accordingto the value in the BSR of the new-transmission user, wherein the otherusers refer to all online users in the serving cell to which thenew-transmission user belongs but excluding users just getting online inthe current TTI, retransmission users, new-transmission users alreadyscheduled prior to scheduling this new-transmission user, and thisnew-transmission user itself; and

when determining that the average rate of a new-transmission user isless than the GBR, determine a number of RBs for a new-transmission useraccording to the value in the BSR of the new-transmission user.

Preferably, when determining that the average rate of thenew-transmission user is greater than or equal to the GBR but less thanor equal to the MBR, the resource scheduling unit may be furtherconfigured to, when the BSR of the user is greater than the GBR, addthis user to a user list in which the number of RBs for the user islimited and the average rate of the user reaches the GBR; if there areremaining RB resources after other users are all allocated with RBresources, allocate the RB resources to the users in the user list ofwhich a limited RB number has reached the GBR.

In the disclosure, according to the PF scheduling algorithm inconjunction with QoS of the GBR service of each user, the schedulingpriority of each user is determined, so as to enable the service tosatisfy the GBR rate as far as possible on the premise of guaranteeingscheduling fairness. With the scheduling method of the disclosure, theRB resources can be fully utilized, and the user rate which does notreach GBR is quickly improved to make as many users as possible to reachthe GBR, so as to increase the number of satisfied users in system. Forthe case in which an MBR is greater than the GBR, on the basis that asmany users as possible are made to reach the GBR, the rate of users canbe further improved to increase the number of users with high rates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart of a method for scheduling a GBR service basedon QoS according to Embodiment 1 of the disclosure;

FIG. 2 shows a flowchart of a method for scheduling a GBR service basedon QoS according to Embodiment 2 of the disclosure;

FIG. 3 shows a simulation diagram of both MBR and GBR being equal to 200Kbps according to Embodiment 1 of the disclosure;

FIG. 4 shows a simulation diagram of both MBR and GBR being equal to 300Kbps according to Embodiment 1 of the disclosure;

FIG. 5 shows a simulation diagram of MBR being 350 Kbps and GBR being200 Kbps according to Embodiment 2 of the disclosure;

FIG. 6 shows a simulation diagram of MBR being 400 Kbps and GBR being300 Kbps according to Embodiment 2 of the disclosure; and

FIG. 7 shows a structure of an apparatus for scheduling a GBR servicebased on QoS according to the disclosure.

DETAILED DESCRIPTION

For a better understanding, technical schemes and advantages of thedisclosure and embodiments are provided below to further illustrate thedisclosure in detail by reference to accompanying drawings.

Two embodiments hereinafter are illustrated by taking a 10 MHz-bandwidthLong Term Evolution (LTE) downlink system of a macro eNodeB as anexample. Basic parameters and parameters adopted by system simulationare shown in Table 1.

TABLE 1 Parameter Items Value Drop number 1 Simulation TTI number per1600TTI Drop Warmup TTI number 500 Networking mode 3-sectorizedHexagonal grid Site number 7sites, Wrap around ISD (site spacing) 1000 mFrequency multiplexing 1 Multi-antenna technology RANK adaptation BStransmit power 46 dBm BS antenna configuration 2TX (10lamda) BS noisecoefficient 5 dB BS antenna gain 17 dB UE transmit power 23 dBm UEantenna configuration 2 RX UE noise coefficient 9 dB UE antenna gain 0dB Antenna mode Measured data for vertical pattern. Back loss = −25 dBfor horizontal Back loss = −20 dB for vertical Back loss = −25 dB forwhole pattern Angle of elevation calculated by a ratio of actual heightdifference to horizontal projection distance UE distribution Uniformlydropped in each cell Carrier frequency band 2.0 GHz System bandwidth 10MSimulation scene Dense urban Large-Scale Fading 3GPP M1225: PL = 128.1 +37.6 log (d), d in km Shadow correlation distance 50 m Shadowcorrelation 0.5 coefficient between cells Shadow correlation 1coefficient between sectors Penetration Loss 20 dB User service modelNGMN service model Scheduler Fair Factor: FF = FF_(PF) · FF_(GBR)

Based on a service model of a Next Generation Mobile Network (NGMN)technology development organization, a scene with great load isselected, wherein the size of a data packet of a user is set to be0.16M, new data is inserted into a Buffer Status Report (BSR) accordingto the size of MBR in each TTI, thus, in this way, the user rate wouldnot be greater than the MBR, provided that all users in the system havethe same GBR service requirement. The essence of the technical scheme ofthe disclosure is further illustrated below in conjunction with specificembodiments.

Embodiment 1

This embodiment is designed for the condition that the MBR of a user isequal to the GBR, that is, for inserting new data into a BSR accordingto the size of GBR in each TTI.

When new data is inserted into the BSR according to the size of GBR ineach TTI, once the user retransmits, the rate would be less than theGBR. Thus, in the condition of MBR=GBR, there would be many users havingrates less than the GBR instantaneously. At this moment, a fast measureshould be adopted: for the user having a rate less than the GBR, thenumber of RBs is determined according to a value in the BSR; for theuser having a rate greater than or equal to the GBR, the number of RBsis determined by taking a smaller value of the GBR and the BSR.

FIG. 1 shows a flowchart of a method for scheduling a GBR service basedon QoS according to Embodiment 1 of the disclosure; as shown in FIG. 1,the method for scheduling a GBR service based on QoS comprises thefollowing steps:

Step 11: calculate an average history throughput rate of an online user(that is, an average rate of a user) in a system in a current TTI. Thecalculation formula is as follows:

${Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\;\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2}} \right)}{N}$

In the formula above, N represents a set window length and generallytakes a value of 1024; however, the value can also be set according tothe system requirement and the actual scheduling scene. This embodimentis illustrated by taking a user simultaneously having two GBR serviceflows for example; if a user has multiple GBR service flows, the formulaabove can also determine the average rate. TB_1 (the first flow) andTB_2 (the second flow) represent a TB Size scheduled once in the windowtime respectively; if no scheduling is performed, TB_1 and TB_2 take avalue of 0. ACK_1 and ACK_2 represent Hybrid Automatic Repeat Request(HARQ) acknowledgment information about whether TB_1 and TB_2 aretransmitted successfully received by an eNodeB (for a downlink); the ACKtakes a value of 1 when a transmission is success, and takes a value of0 when it fails.

Step 12: a base station queues each user terminal by a priorityaccording to a scheduling algorithm.

The scheduling algorithm in Step 12 is an algorithm integrating the PFand the QoS of the GBR service, wherein a comprehensive priority (FF) ofa user is as follows:FF=FF_(PF)·FF_(GBR)

where FF_(PF) represents a fair factor calculated by a (general) PFalgorithm (G-PF);

${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}\;{{TB}(i)}}{1 + {HistoryThroughput}}},$where the numerator represents a TB Size transmitted successfully in NTTIs (the selected window length), the HistoryThroughput in thedenominator represents the average history throughput rate of a userobtained in Step 11, and “·” represents scalar multiplication.

FF_(GBR) represents a fair factor of the GBR scheduling.

${{FF}_{{GBR}\;} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {HistoryThroughput}}}},$where the GBR in the numerator of the index represents a guaranteed bitrate configured by a system, ThresholdGBR represents a GBR reservedproportion, which is equivalent to an fluctuation amplitude threshold ofthe GBR, for example, ThresholdGBR=10%; the HistoryThroughput in thedenominator of the index represents the average history throughput rateof a user obtained in Step 11.

According to the calculation result in this step, users are sorted bypriorities, wherein the user with a highest priority is queued in themost front of the queue.

Step 13: schedule a retransmission user according to the user priorityobtained in Step 12, wherein the number of RBs of the retransmissionuser depends on the retransmitted TB Size and is not limited by a GBRfactor.

Step 14: schedule a new-transmission user according to the user priorityobtained in Step 12.

Step 14 may further include the following steps:

Step 141: determine whether the rate of the user obtained in Step 11 isless than the GBR, if yes, go to Step 142, otherwise, go to Step 143.

Step 142: if the average rate of the user is less than the GBR,determine the number of RBs according to the RB number RB_(Rank·) ^(BSR)needed by the value in the BSR, and then take a smaller value of theRB_(Rank·) ^(BSR) and the number of current remaining RBs.

That is, RB_(Last)=min(RB_(Rank·) ^(BSR), RB_(Rest)).

If the user adopts single-flow transmission,

${{RB}_{{Rank}\; 1}^{BSR} = \frac{{BSR} + {Head} + {CRC}}{N_{SC}^{RB} \cdot N_{Sym}^{TTI} \cdot {SE}_{1}}};$or

if the user adopts double-flow transmission,

${RB}_{{Rank}\; 2}^{BSR} = {\frac{{BSR} + {2 \cdot {Head}} + {2 \cdot {CRC}}}{N_{SC}^{RB} \cdot N_{Sym}^{TTI} \cdot \left( {{SE}_{1} + {SE}_{2}} \right)}.}$

In the formula above, Head represents the bit number of MAC head and is16 bits in an LTE system; CRC represents a length of Cyclic RedundancyCheck (CRC) and is 24 bits in the LTE system; N_(SC) ^(RB) representsthe number of sub-carriers contained in each RB and takes a value of 12when the sub-carrier spacing is 15 KHz and a value of 24 when thesub-carrier spacing is 7.5 KHz; N_(Sym) ^(TTI) represents the number ofavailable symbols in each TTI, and takes a value of 10 in a common CPand a value of 8 in an extended CP; SE₁ represents a spectrum efficiencycorresponding to the CQI of a single flow or the CQI of a first flow(with a unit of bit/Symbol); SE₂ represents a spectrum efficiencycorresponding to the CQI of a second flow of double flows, wherein theCQI is the wideband CQI reported by the user.

Step 143: if the average rate of the user is greater than or equal tothe GBR, determine the number of RBs according to a smaller valueRB_(Rank) ^(Min) of the GBR and the BSR and take a smaller value of theRB_(Rank) ^(Min) and the number of current remaining RBs.

That is, RB_(Last)=min(RB_(Rank·) ^(Min), RB_(Rest)).

If the user adopts single-flow transmission,

${{RB}_{{Rank}\; 1}^{Min} = {{Ceil}\left( \frac{{{\min\left( {{BSR},{{GBR} \cdot {TTI}}} \right)} \cdot {EP} \cdot {Header}} + {CRC}}{N_{SC}^{RB} \cdot N_{Sym}^{TTI} \cdot {SE}_{1}} \right)}};$or

If the user adopts double-flow transmission,

${RB}_{{Rank}\; 2}^{Min} = {{{Ceil}\left( \frac{{{\min\left( {{BSR},{{GBR} \cdot {TTI}}} \right)} \cdot {EP} \cdot {Header}} + {2 \cdot {CRC}}}{N_{SC}^{RB} \cdot N_{Sym}^{TTI} \cdot \left( {{SE}_{1} + {SE}_{2}} \right)} \right)}.}$

In the formula above, Ceil(·) represents a ceiling operation; min(·)represents an operation of taking a smaller one from two; BSR representsthe bit number catched by a Dedicated Transmission Channel (DTCH); GBRrepresents a guaranteed bit rate of the GBR service (with a unit ofkbps); EP represents a rate enhancement proportion (with a purpose ofpreventing in advance service rate reduction caused by error block);Header represents a proportion to be enhanced since RLC/PDCP has anoverhead such as Head/Padding; TTI represents a duration of a TTI (here,it is 1 ms); SE₂ represents a spectrum efficiency of a second flow(corresponding to the CQI of the second GBR service flow).

Step 15: enter a next TTI, repeat Step 11 to Step 14.

FIG. 3 shows a simulation diagram of both MBR and GBR being equal to 200Kbps according to Embodiment 1 of the disclosure; FIG. 4 shows asimulation diagram of both MBR and GBR being equal to 300 Kbps accordingto Embodiment 1 of the disclosure. With reference to FIG. 3 and FIG. 4,in the scene of Embodiment 1, the simulation shows that the schedulingscheme for a GBR service in the disclosure can fully guarantee the GBRrate of users, especially of edge users. The simulation system in thedisclosure is a commercially available LTE simulation system.

Embodiment 2

This embodiment is designed for the condition that the MBR of a user isgreater than the GBR, that is, for inserting new data into a BSRaccording to the size of the MBR in each TTI.

Compared with Embodiment 1, the basic idea of Embodiment 2 is the sameas that of Embodiment 1. That is, the number of RBs of users reachingthe GBR rate is limited and the remaining RB resources are allocated tousers not reaching the GBR rate. In this way, the user not reaching theGBR rate may have adequate RB resources to transmit more data, thus thetransmission rate is improved to reach the GBR rate. The difference isthat Embodiment 2 refines the users reaching the GBR rate with RB numberbeing limited. On the basis of guaranteeing the GBR rate of edge users,the RB resources are fully utilized to further improve the user rate, sothat more users can enjoy higher rate QoS on the basis of the usersbasically having the GBR rate.

FIG. 2 shows a flowchart of a method for scheduling a GBR service basedon QoS according to Embodiment 2 of the disclosure; as shown in FIG. 2,the method for scheduling a GBR service based on QoS comprises thefollowing steps:

Step 21: calculate an average history throughput rate of an online user(that is, an average rate of a user) in a system in a current TTI. Thecalculation formula is the same as that in Step 11 in Embodiment 1 andthe description thereof is omitted here.

Step 22: an eNodeB queues each user terminal by a priority according toa scheduling algorithm. The calculation formula of the user priority isthe same as that in Step 12 in Embodiment 1 and the description thereofis omitted here.

Step 23: schedule a retransmission user according to the user priorityobtained in Step 22, wherein the number of RBs of the retransmissionuser depends on the retransmitted TB Size and is not limited by a GBRfactor.

Step 24: schedule a new-transmission user according to the user priorityobtained in Step 22.

Step 24 may further comprise the following steps:

Step 241: queue a new-transmission user according to the user priorityobtained in Step 22.

Step 242: for a new-transmission user Uei being scheduled, if theaverage rate of the user Uei is less than the GBR, it is determined thatthe number of RBs RB_(Rank) ^(BSR) according to the value in a BSR ofthe user Uei, and a smaller value of RB_(Rank) ^(BSR) and the number ofcurrent remaining RBs is taken. The calculation formula of RB_(Rank)^(BSR) is the same as that in Step 142 in Embodiment 1. If the averagerate of the user Uei is greater than or equal to the GBR, go to Step243.

Step 243: for a new-transmission user Uei being scheduled, establish alist of other online users in a cell, and remove retransmission users,users just getting online in the current TTI, and new-transmission usersscheduled prior to the Uei from the list. If the list of users otherthan the Uei is not empty and there is a user in the list having anaverage rate less than the GBR, go to Step 244, otherwise, go to Step245.

Step 244: according to a smaller value RB_(Rank) ^(Min) of the requiredGBR and the BSR of the user Uei, determine the number of RBs allocatedto the user Uei, and take a smaller value of the number of RBs and thenumber of remaining RBs. The calculation formula of the RB_(Rank) ^(Min)is the same as that in Step 143 in Embodiment 1. Then, go to Step 246.

Step 245: according to the value in the BSR of the user Uei, determinethe number of RBs RB_(Rank) ^(BSR) allocated to the user Uei, and take asmaller value of RB_(Rank) ^(BSR) and the number of remaining RBs. Thecalculation formula of RB_(Rank) ^(BSR) is the same as that in Step 142in Embodiment 1. Then, go to Step 246.

Step 246: schedule a next new-transmission user according to thepriority of the new-transmission user obtained in Step 241, and repeatStep 242 to Step 245 until all the RB resources are used up or allnew-transmission users are scheduled.

Step 25: enter a next TTI and repeat Step 21 to Step 24.

With reference to FIG. 3, FIG. 4, FIG. 5 and FIG. 6, in the scene of thetwo embodiments above, the simulation shows that the scheduling schemefor a GBR service in the disclosure can guarantee the GBR rate of users,especially of edge users. In the scene of MBR>GBR, on the basis ofguaranteeing the GBR rate of edge users, the disclosure can furtherimprove the average rate of center users.

FIG. 5 shows a simulation diagram of MBR being 350 Kbps and GBR being200 Kbps according to Embodiment 2 of the disclosure. FIG. 6 shows asimulation diagram of MBR being 400 Kbps and GBR being 300 Kbpsaccording to Embodiment 2 of the disclosure. With reference to FIG. 5and FIG. 6, the simulation shows that the scheduling scheme for a GBRservice in the disclosure can guarantee the GBR rate of users,especially of edge users. In the scene of MBR>GBR, on the basis ofguaranteeing the GBR rate of edge users, the disclosure can furtherimprove the average rate of center users.

FIG. 7 shows a structure of an apparatus for scheduling a GBR servicebased on QoS according to the disclosure. As shown in FIG. 7, theapparatus for scheduling a GBR service based on QoS according to thedisclosure comprises a determining unit 71 and a resource schedulingunit 72.

The determining unit 71 is configured to determine a scheduling priorityof each user according to an average rate of a GBR service of eachonline user in a current TTI.

The resource scheduling unit 72 is configured to schedule the users inaccordance with determined priorities and allocate RB resources to theusers.

The determining unit 71 is further configured to determine thescheduling priority of each user according to a PF scheduling algorithmand in conjunction with QoS of the GBR service of each user.

Preferably, the determining unit 71 is further configured to determine ascheduling priority FF of a user according to following formula:FF=FF_(PF)·FF_(GBR)

where

${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}\;{{TB}(i)}}{1 + {Th}_{His}}},{{FF}_{{GBR}\;} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {Th}_{His}}}},$“·” represents a scalar multiplication; Th_(His) represents an averagerate of the GBR service in N TTIs selected prior to the current TTI;TB(i) represents TBs transmitted successfully in the N TTIs; andThresholdGBR represents a GBR reserved proportion set by a system.

The determining unit 71 is further configured to determine Th_(His)according to the following formula:

${{Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\;\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2} + \ldots + {{TB\_ m} \cdot {ACK\_ m}}} \right)}{N}},$where N

represents a selected window length; TB_1 to TB_m represent TB Sizesscheduled once for respective GBR service streams 1 to m in the TTI; andACK_1, ACK_2 and ACK_m take a value of 1 when a corresponding TB istransmitted successfully and a value of 0 when the corresponding TBfails to be transmitted.

The resource scheduling unit 72 is further configured to:

schedule retransmission users in accordance with a priority order,wherein the number of RBs of a retransmission user depends on theretransmitted TB Size and is not limited by a GBR factor; and

if there are RB resources left after all retransmission users arescheduled, schedule new-transmission users in accordance with a priorityorder and allocate a number of RBs to the new-transmission usersaccording to the QoS determined by the GBR service of thenew-transmission user.

The resource scheduling unit 72 is further configured to:

do not schedule a new-transmission user, when determining that theaverage rate of the new-transmission user is greater than an MBR;

determine a number of RBs for a new-transmission user according to asmaller value of the GBR and a BSR of the new-transmission user, whendetermining that the average rate of the new-transmission user isgreater than or equal to the GBR but less than or equal to the MBR andfurther determining that there are other users with rates less than theGBR in the current cell; determine a number of RBs for thenew-transmission user according to the value in the BSR of thenew-transmission user, when determining that the average rates of theother users in the current cell are greater than or equal to the GBR;and

determine a number of RBs for a new-transmission user according to thevalue in the BSR of the new-transmission user, when determining that theaverage rate of the new-transmission user is less than the GBR.

When determining that the average rate of the new-transmission user isgreater than or equal to the GBR but less than or equal to the MBR, theresource scheduling unit 72 is further configured to add this user to auser list of which a limited RB number has reached the GBR, when the BSRof the user is greater than the GBR; and if RB resources are left afterother users are all allocated with RB resources, allocate RB resourcesto the user in the user list of which a limited RB number has reachedthe GBR.

Those skilled in the art should understand that the apparatus forscheduling a GBR service based on QoS shown in FIG. 7 is designed forimplementing the method for scheduling a GBR service based on QoSdescribed above. The function of each processing unit included in theapparatus shown in FIG. 7 can be understood by reference to thedescription of Embodiment 1 and Embodiment 2, wherein the function ofeach processing unit can be implemented by a program running on aprocessor, or can be implemented by a specific logic circuit.

The above is only the preferred embodiments of the disclosure and is notintended to limit the protection scope of the disclosure.

What is claimed is:
 1. A method for scheduling a Guaranteed Bit Rate(GBR) service based on Quality of Service (QoS), comprising: determininga scheduling priority of an online user according to an average rate ofa GBR service of the user in a current Transmission Time Interval (TTI);and scheduling the user in accordance with the determined priority andallocating Resource Block (RB) resources to the user; wherein thescheduling the user in accordance with the determined priority andallocating the RB resources to the user comprises: schedulingretransmission users in accordance with a priority order, wherein anumber of RBs of each retransmission user depends on a retransmitted TBSize and is not limited by a GBR factor; and scheduling new-transmissionusers in accordance with the priority order, and allocating RBs to eachnew-transmission user according to QoS determined by the GBR service ofeach new-transmission user, when there are remaining RB resources afterall retransmission users are scheduled.
 2. The method according to claim1, wherein the determining the scheduling priority of the online useraccording to the average rate of the GBR service of the user in thecurrent TTI comprises: determining the scheduling priority of the useraccording to a Proportional Fair (PF) scheduling algorithm inconjunction with QoS of the GBR service of the user.
 3. The methodaccording to claim 2, wherein the determining the scheduling priority ofthe user according to the PF scheduling algorithm in conjunction withQoS of the GBR service of the user is determining a scheduling priorityFair Factor (FF) of the user according to a following formula:FF=FF_(PF)·FF_(GBR) where${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}\;{{TB}(i)}}{1 + {Th}_{His}}},{{FF}_{{GBR}\;} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {Th}_{His}}}},$“·” represents a scalar multiplication, Th_(His) represents an averagerate of the GBR service in N TTIs selected prior to the current TTI,TB(i) represents Transmission Blocks (TBs) transmitted successfully inthe N TTIs, ThresholdGBR represents a GBR reserved proportion set by asystem, and GBR in the numerator of the index represents a guaranteedbit rate configured by the system.
 4. The method according to claim 3,wherein Th_(His) is determined according to a following formula:${{Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\;\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2} + \ldots + {{TB\_ m} \cdot {ACK\_ m}}} \right)}{N}},$where N represents a selected window length, m represents a number ofGBR service streams of the user in the N TTIs, TB_1 to TB_m represent TBSizes scheduled once for respective GBR service streams 1 to m in theTTI, and ACK_1, ACK_2 and ACK_m take a value of 1 when a correspondingTB is transmitted successfully and a value of 0 when the correspondingTB fails to be transmitted.
 5. The method according to claim 1, whereinthe allocating RBs to each new-transmission user according to the QoSdetermined by the GBR service of each new-transmission user comprises:not scheduling a new-transmission user, when determining that theaverage rate of the new-transmission user is greater than a Maximum BitRate (MBR); determining a number of RBs for a new-transmission useraccording to a smaller value of the GBR and a Buffer Status Report (BSR)of the new-transmission user, when determining that the average rate ofthe new-transmission user is greater than or equal to the GBR but lessthan or equal to the MBR and further determining that there are otherusers with rates less than the GBR in a current cell; determining anumber of RBs for the new-transmission user according to a value in theBSR of the new-transmission user, when determining that the averagerates of the other users in the current cell are greater than or equalto the GBR; wherein the other users refer to all online users in theserving cell to which the new-transmission user belongs but excludingusers just getting online in the current TTI, retransmission users,new-transmission users already scheduled prior to scheduling thisnew-transmission user, and this new-transmission user itself; anddetermining a number of RBs for a new-transmission user according to thevalue in the BSR of the new-transmission user, when determining that theaverage rate of the new-transmission user is less than the GBR.
 6. Themethod according to claim 5, further comprising: when determining thatthe average rate of the new-transmission user is greater than or equalto the GBR but less than or equal to the MBR: adding this user to a userlist in which the number of RBs for the user is limited and the averagerate of the user reaches the GBR, when the BSR of the user is greaterthan the GBR; and allocating RB resources to the user in the user listof which the limited RB number has reached the GBR, when there areremaining RB resources after other users are all allocated with RBresources.
 7. An apparatus for scheduling a Guaranteed Bit Rate (GBR)service based on Quality of Service (QoS), comprising a determining unitand a resource scheduling unit, wherein the determining unit isconfigured to determine a scheduling priority of an online useraccording to an average rate of a GBR service of the user in a currentTransmission Time Interval (TTI); and the resource scheduling unit isconfigured to schedule the user in accordance with the determinedpriority and allocate Resource Block (RB) resources to the user; whereinthe resource scheduling unit is further configured to: scheduleretransmission users in accordance with a priority order, wherein anumber of RBs of each retransmission user depends on a retransmitted TBSize and is not limited by a GBR factor; and schedule new-transmissionusers in accordance with the priority order, and allocate RBs to eachnew-transmission user according to QoS determined by the GBR service ofeach new-transmission user, when there are remaining RB resources afterall retransmission users are scheduled.
 8. The apparatus according toclaim 7, wherein the determining unit is further configured to determinethe scheduling priority of the user according to a Proportional Fair(PF) scheduling algorithm in conjunction with QoS of the GBR service ofthe user.
 9. The apparatus according to claim 8, wherein the determiningunit is further configured to determine a scheduling priority FairFactor (FF) of the user according to a following formula:FF=FF_(PF)·FF_(GBR) where${{FF}_{PF} = \frac{\sum\limits_{i = 1}^{N}\;{{TB}(i)}}{1 + {Th}_{His}}},{{FF}_{{GBR}\;} = {\mathbb{e}}^{\frac{{GBR} \cdot {({1 + {ThresholdGBR}})}}{1 + {Th}_{His}}}},$“·” represents a scalar multiplication, Th_(His) represents an averagerate of the GBR service in N TTIs selected prior to the current TTI,TB(i) represents Transmission Blocks (TBs) transmitted successfully inthe N TTIs, ThresholdGBR represents a GBR reserved proportion set by asystem, and GBR in the numerator of the index represents a guaranteedbit rate configured by the system.
 10. The apparatus according to claim9, wherein the determining unit is further configured to determineTh_(His) according to a following formula:${{Th}_{His} = \frac{\sum\limits_{i = 1}^{N}\;\left( {{{TB\_}{1 \cdot {ACK\_}}1} + {{TB\_}{2 \cdot {ACK\_}}2} + \ldots + {{TB\_ m} \cdot {ACK\_ m}}} \right)}{N}},$where N represents a selected window length, m represents a number ofGBR service streams of the user in the N TTIs, TB_1 to TB_m represent TBSizes scheduled once of respective GBR service streams 1 to m in theTTI, and ACK_1, ACK_2 and ACK_m take a value of 1 when a correspondingTB is transmitted successfully and a value of 0 when the correspondingTB fails to be transmitted.
 11. The apparatus according to claim 7,wherein the resource scheduling unit is further configured to: notschedule a new-transmission user, when determining that the average rateof the new-transmission user is greater than a Maximum Bit Rate (MBR);determine a number of RBs for a new-transmission user according to asmaller value of the GBR and a Buffer Status Report (BSR) of thenew-transmission user, when determining that the average rate of thenew-transmission user is greater than or equal to the GBR but less thanor equal to the MBR and further determining that there are other userswith rates less than the GBR in a current cell; determine a number ofRBs for the new-transmission user according to a value in the BSR of thenew-transmission user, when determining that the average rates of theother users in the current cell are greater than or equal to the GBR;wherein the other users refer to all online users in the serving cell towhich the new-transmission user belongs but excluding users just gettingonline in the current TTI, retransmission users, new-transmission usersalready scheduled prior to scheduling this new-transmission user, andthis new-transmission user itself; and determine a number of RBs for anew-transmission user according to the value in the BSR of thenew-transmission user, when determining that the average rate of thenew-transmission user is less than the GBR.
 12. The apparatus accordingto claim 11, wherein the resource scheduling unit is further configuredto: when determining that the average rate of the new-transmission useris greater than or equal to the GBR but less than or equal to the MBR,add this user to a user list in which the number of RBs for the user islimited and the average rate of the user reaches the GBR, when the BSRof the user is greater than the GBR; and allocate RB resources to theuser in the user list of which a limited RB number has reached the GBR,when there are remaining RB resources after other users are allallocated with RB resources.